Investments - Summary of Selected Financial Information for Jefferies LoanCore (Detail) (Jefferies LoanCore, LLC [Member], USD $)	Feb. 28, 2015	Nov. 30, 2014
Jefferies LoanCore, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Total assets	$ 2,043,000,000	$ 1,500,900,000
Total liabilities	1,417,200,000	962,700,000
Total equity	625,800,000	538,200,000
Our total equity balance	$ 303,500,000	$ 261,000,000